In the chemical and in particular the petroleum industry, it is frequently necessary to remove water from air before it can be used. Dried air, for instance, is used to mix with residual natural gas in order to control the heating value of this gas. Another application of dry air is in the field of tools operating with compressed air.
Moist air, particularly when compressed to high pressure, can be very corrosive to equipment. Compressing air of 20 percent relative humidity, atmospheric pressure and a temperature of 80.degree. F to 100 psia and a temperature of 100.degree. F, for instance, increases the relative humidity of such air to 74 percent.
It is well known in the art that moist air can be dried by contacting it with a glycol. During this process, the glycol is enriched with water and also with some air. In order to reuse the glycol, it is common practice to remove the water by heating the used wet glycol, e.g., to a temperature of 380.degree. F when using triethylene glycol. After a certain period of time, however, the glycol must be replaced. Among other reasons, the replacement of the glycol is necessitated by the production of corrosive acidic by-products.